"Our air force personnel has started training in the Russian town of Gatchina to operate S-400 missile defense systems," the ministry informed on Twitter.

Earlier, head of the Almaz-Antey arms company Yan Novikov informed that Turkish personnel training would last from September 1, 2019 to January 2, 2020.

On August 27, Russia began deliveries of the second batch of S-400 to Turkey.

In September 2017, Russia informed of a contract signed with Turkey on the purchase of Russian-made S-400 missile defense systems to the tune of $2.5 bln. The contract includes partial disclosure of production technology to the Turkish side. The first batch of S-400 was delivered to Turkey from July 12 to July 25. The second batch is set to be delivered in full by late September.